Distinction between people with TB infection and disease
-only 7- 10% infected people develop disease in their lifetimes (the remainder have latent infections)
What percent of AIDS patients who are infected with TB will develop active disease?
10%
People who are most likely to be infected with TB?
- Close contacts of active disease
- Foreign-born persons from areas where TB is common
- Residents of long term care facilities
- Persons who inject drugs
People most likely to progress to TB disease
- HIV infection
- Recently infected within last 2 years
TB Transmission
Almost exclusively airborne
TB Pathogenesis
- Droplet nucleus (alveolar macrophage access)
- Regional lymph node and blood borne spread
TB Immunopathogenesis
TB antigens leads lymphoproliferation and cytokine production causing granuloma formation and tissue destruction
TB Diagnosis H & P
non-specific
TB Diagnosis Radiographic examination
-Upper lung field infiltrates and cavities
TB Diagnosis Labs
- Tuberculin (PPD) Skin test
- Sputum “AFB” smears Acid Fast
- NAAT (PCR)
What are Nontuberculous Mycobacteria (NTM)?
environmental pathogens that affect predisposed hosts
Where are NTM found?
- Bioaerosols
- Water
- Soil
What is a predisposing factor for NTM?
a structural lung abnormality
Differences between TB and NTM?
- NTM is environmental in origin, TB is human-to-human transmission
- NTM requires an underlying predisposition and does not have a long latent phases
